@startuml
object Customer {
    customerId: int
    firstName: string
    lastName: string
}

object Item {
    itemId: int
    description: string
    price: money
}

object Merchant {
    merchantId: int
    merchantName: string
    merchantAddress: string
}

object CustomerOrder {
    customerOrderId: int
    customerId: int
    merchantId: int
}

object CustomerOrderItem {
    customerOrderItemId: int
    customerOrderId: int
    itemId: int
    quantity: int
}

CustomerOrderItem "1..*" -- "1" CustomerOrder
CustomerOrder "1" -- "1" Merchant
CustomerOrderItem "1" -- "1" Item
CustomerOrder "1..*" -- "1" Customer
@enduml